MIPS: Excite: move iodev_remove to .devexit.text

The function iodev_remove is used only wrapped by __devexit_p so define
it using __devexit.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/710/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>